Fusehead



l atented May 9, I933;

NITED STATES PATENT OFFICE WILLIAM OSWALD LITTLEBURY, OF ARDROSSAN,SCOTLAND, ASSIGNOR TO IMPERIAL CHEMICAL INDUSTRIES LIMITED, ACORPORATION OF GREAT BRITAIN FUSEHIEAD No Drawing. Application filedFebruary 17, 1932, Serial No. 593,695, and in Great Britain February 18,1931.

bers into a suspension of a suitable priming composition in a solutionof nitrocellulose in volatile organic solvents, the bead of suspensionbeing then dried to form the fusehead. Inthe case of low-tensionfuseheads the pole members are joined by a fine wire bridge throughwhich the current is passed for ignition purposes, while in the case ofhigh-tension fuseheads the wire bridge is dispensed with and thefusehead itself acts as the conductor, a suitable conducting ingredient,e. g. graphite, being included in the composition for this purpose.

According to the invention a composition for a fusehead adapted forelectrical firing comprises in addition to the primary ignitingcomposition a proportion of tetrazene(guanylnitrosamino-guanyltetrazene) up to 50 per cent. of the totalcomposition. The proportion of tetrazene may vary from a few per cent.up to 50 per cent. according to the nature of the priming charge withwhich it is mixed.

The invention is particularly adapted for use in connection with primingcharge compositions consisting of or containing lead salts ofnitro-phenols'and the like, e. g. lead salts of trinitroresorcinol,2-mono-nitroresorsinal, dinitrosalicyclic acid, and dior trinitrophenol.I

, Thus in the case of a low tension fusehead comprising a priming chargeof basic lead mononitroresorcinate, the firing current was reduced from0.48 ampere t0-0.38 ampere by the inclusion of 10 per cent of tetrazene.

In the case of a high tension fusehead comprising a priming charge ofbasic lead mononitroresorcinate containing graphite, the firing voltagewas reduced from 41 volts to 28 volts by the inclusion of 10 per cent.of tetraabout 16:100.

While varying amounts of tetrazene may be used in the composition, Ifind the results to be very satisfactory when the weights of leadmononitroresorcinate and tetrazene present are in the proportion of 100to 16, suflicient graphite being present to produce the requiredelectrical resistance.

As many apparently widely different embodiments of this invention may bemade without departing from-the spirit and scope thereof, it is to beunderstood that we do not limit ourselves to the specific embodimentsthereof except as defined in the appended claims.

I claim 1. A fusehead composition adapted for electrical firingwhichcomprises, in addition to the primary igniting composition, a proportionof tetrazene'up to 50 per cent. of the total composition. i

2. A fusehead composition adapted for electrical firing which comprises,in addition to a primary igniting composition consisting of a lead saltof a nitrophenolic body, a proportion of tetrazene up to 50 per cent. ofthe total composition.

3. A fusehead composition adapted for electrical firing which comprises,in addition to a primary igniting composition consisting of leadmononitroresorcinate, a proportion of tetrazene up to 50 per cent. ofthe total composition.

4. A low-tension fusehead adapted for electrical firing, in which theprimary igniting mixture consists of 90 per cent. by weight of leadmononitroresorcinate and 10 per cent by weight of tetrazene.

5. A high-tension fusehead adapted for electrical firing, in which theprimary igniting composition consists of 100 parts by weight of leadmononitroresorcinate and 16 parts by weight of tetrazene to which hasbeen added suflicient graphite to produce the required electricalresistance.

In testimony whereof he affixes his signature.

WILLIAM OSWALD LITTLEBURY.

